Method and system for providing enhanced caller identification information for subscribers that interface via private trunk groups

ABSTRACT

A system and method deliver audible caller identification information when standard Caller ID information is invalid or can not be provided, even when the called party connects to the network by private trunk group facilities. In one disclosed embodiment, a trunk group trigger associated with the called communication station is encountered, launching a termination attempt query. If standard caller identification information can not be provided for the calling party, the call will be routed to a privacy service to obtain the audible caller identification information.

RELATED APPLICATIONS

The present patent document is a continuation of U.S. application Ser.No. 10/931,283, filed on Aug. 31, 2004 now U.S. Pat. No. 7,272,219 whichis a continuation of U.S. application Ser. No. 10/036,950, filed Dec.21, 2001, now U.S. Pat. No. 6,807,267, the content of U.S. patentapplication Ser. No. 10/036,950 is hereby incorporated herein in itsentirety by this reference.

BACKGROUND

The present invention relates generally to telecommunications services.More particularly, the present application relates to a method andsystem for providing enhanced caller identification information even tosubscribers who interface the telecommunication network via privatetrunk group facilities.

Telecommunications service providers typically offer services thatattempt to provide customers with information that enables them todetermine whether or not to accept a call before answering the call. Oneservice that provides such information is caller identification (“CallerID”). Standard Caller ID services generally provide a customer with anindication of who is calling without requiring the customer to answerthe call. These systems typically retrieve information about the callingparty from a database and provide that information to the called party.Customer premise equipment (CPE) in the form of a display device isgenerally used to provide the called party with a visual readout of thename and/or telephone number associated with the calling party.

However, the effectiveness of Caller ID systems can be reduced due to anumber of different occurrences. One such occurrence is the inability ofa service provider to provide the standard Caller ID information for aparticular incoming call. A service provider may not be able to providethe standard Caller ID information if the Caller ID information isblocked by the calling party, or if the Caller ID information isunavailable or incomplete. This may occur, for example, if the callingparty pressed *67 when initiating the call

When the standard Caller ID information cannot be provided, the calledparty is not adequately informed about who is calling and cannotdetermine whether or not to accept the incoming call before answeringthe call. Because the effectiveness of Caller ID systems is greatlyreduced when information cannot be provided, an improved system andmethod for providing caller identification information that overcomethese deficiencies are needed.

Patent application Ser. No. 09/122,484, filed Jul. 24, 1998, issued Jan.23, 2001 as U.S. Pat. No. 6,178,232 and commonly assigned to theassignee of the present application, is incorporated herein byreference. This patent application discloses a method and system forproviding a called party with audible caller identification informationwhen standard caller identification cannot be provided. When standardcaller identification cannot be provided, the call is blocked and arequest for audible caller identification is transmitted to the callingparty. The audible information is subsequently transmitted to the calledparty.

Patent application Ser. No. 09/253,339, filed Feb. 19, 1999 and issuedDec. 12, 2000 as U.S. Pat. No. 6,160,876, is also incorporated herein byreference. This application discloses a method for providing enhancedcaller identification information when per line blocking of Caller ID ispresent. When per line blocking is activated for a subscriber line, theCaller ID information for that line is never transmitted by the system.

In the systems disclosed in the incorporated patent applications,subscribers that interface with network equipment via private TrunkGroup facilities can not benefit from those systems. In some embodimentsof those systems, network equipment such as a Service Switching Point(SSP) encounters a terminating attempt trigger when processing a call toa called communication station over a conventional subscriber loop.Encountering the terminating attempt trigger initiates the process ofrouting the call to a privacy service for obtaining audible calleridentification information. However, in the case where the subscriberinterfaces with the network over private Trunk Group facilities, theterminating attempt trigger is never encountered.

Examples of private Trunk Group facilities includes private branchexchanges (PBXs), which are used for example, to providetelecommunication service to a plurality of directory numbers, forexample at a business. The result is that subscribers who access thetelecommunication network over such private facilities can not enjoy thebenefits of privacy service in which callers must provide eitherstandard or audible caller identification information.

Accordingly, there is a need for a system and method which permitsubscribers using private facilities to detect and suspend a call forwhich the standard calling party information can not be provided, beforethe call is communicated to the called party.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a telecommunications system;

FIG. 2 is a call flow diagram illustrating a method for processing acall in the telecommunications system of FIG. 1; and

FIG. 3 is a flow diagram illustrating one embodiment of a method forproviding enhanced caller identification information in accordance withthe privacy management method and system of FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

By way of introduction, the preferred embodiments below include a methodand system for providing a called party with audible calleridentification information when standard caller identificationinformation cannot be provided. In one embodiment, calls for whichstandard caller identification information is blocked, unavailable orincomplete are prevented from being connected to the called party. Ifthe called party directory number indicates that the called party isassociated with a private trunk group or otherwise does not encounter aTerminating Attempt trigger, the call encounters a Trunk Group Trigger,prompting generation of a termination attempt message. The terminationattempt message is analyzed to determine if standard calleridentification information can be provided for the calling party. In oneembodiment, a forward call message is transmitted with the directorynumber of the called party contained in a normally unused data field. Apresentation indicator for the directory number is set in the forwardcall message to presentation allowed so that blocking of the calledparty's identification information does not occur.

In response to the forward call message, a request for audible calleridentification information is transmitted to the calling party. If thecalling party provides the requested audible caller identificationinformation, the audible information is transmitted to the called party.Caller identification information can thus be provided to the calledparty when standard caller identification information cannot beprovided.

Referring now to the drawing, FIG. 1 is a block diagram of atelecommunications system 100. The system 100 comprises a serviceswitching point (SSP) 102, a signal transfer point (STP) 104, a servicecontrol point (SCP) 106, a first SCP database 108, a second SCP database110, a compact service node (CSN) 112, a central office 114, calledtelephone station 116, calling telephone station 118 and a privatebranch exchange (PBX) 120. Intelligent network system components,commonly referred to as advanced intelligent network (AIN) components,suitable for implementing the present embodiment are commerciallyavailable from several vendors and are known to those skilled in theart. AIN components can implement computer readable program code asknown to those skilled in the art. Vendors of AIN components typicallyhave a preferred programming language and operating platform as known tothose skilled in the art.

SSP 102 preferably comprises an AIN switch that routes calls, recognizesand responds to triggers, generates queries to obtain call informationand responds to returned call information. SSP 102 connects to PBX 120and called telephone station 116 over private Trunk Group lines 122.Other type of private facilities or public trunk groups may besubstituted for the PBX 120 and the private Trunk Group lines 122 inother embodiments. The SSP 102 connects the PBX 120 with central office114 to enable calls to be placed between called telephone station 116and calling telephone station 118. SSP 102 preferably communicates withSCP 106, central office 114 and CSN 112 by utilizing a signalingprotocol such as Signaling System 7 (SS7) or other such signalingprotocols as presently known to those skilled in the art or developed inthe future. SSP 102 preferably generates queries to SCP 106 and receivesand responds to responses to the queries returned from SCP 106. In theillustrated embodiment, communication between the SSP 102 and the SCP106 employs Transaction Capabilities Applications Protocol or TCAP.Examples of a suitable switch for embodying the SSP 102 are the 5ESSswitch available from Lucent Technologies and the DMS-100 switchavailable from Nortel Networks.

STP 104 preferably comprises a network element that transfers signalingcommunications in response to signaling protocols such as SS7 or othersuch signaling protocols as presently known to those skilled in the artor developed in the future. STP 104 preferably transfers queries fromSSP 102 to SCP 106 and transfers responses to the queries from SCP 106to SSP 102.

SCP 106 preferably comprises an AIN element that stores accountinformation, call information and receives and responds to queries. SCP106 preferably stores account information about a called party's accountas well as call control information in the first SCP database 108 andcan access the stored information. SCP 106 also stores standard calleridentification information in the second SCP database 110 and can accessthe stored caller identification information. SCP 106 receives queriesgenerated by SSP 102 and preferably responds to the queries byperforming database searches to locate the requested call control oraccount information or caller identification information as known tothose skilled in the art. SCP 106 can forward the call control oraccount information or caller identification information to SSP 102.

CSN 112 preferably comprises a network element that enablescommunications between telephone stations 116, 118 and the network. CSN112 can preferably transmit messages to and receive responses fromtelephone stations 116, 118. CSN 112 can generate announcements that canbe transmitted to telephone stations 116, 118. CSN 112 can transmitresponses such as audible caller identification information fromtelephone station 118 to telephone station 116 by connecting telephonestations 118, 116 or by recording and playing back the responses asknown to those skilled in the art. The announcements transmitted totelephone station 116 preferably comprise accept and reject optionsalong with requests for input from the telephone station 116. Therequests for input preferably comprise requests for input that can beused by CSN 112 to cancel calls to telephone station 116, connect callsto telephone station 116, forward calls to a voice mail system oranother location such as another telephone line, and transmit messagesto telephone station 118. As used herein, the term voice mail systemmeans all types of message recording systems as known to those skilledin the art. CSN 112 can preferably receive and respond to the inputtransmitted from telephone station 116. The term input means anysuitable signal such as DTMF tones, voice input, dial pulse input ormodem/fax input as known to those skilled in the art.

In alternative embodiments, other system equipment may provide thefunctions provided by CSN 112. For example, equivalent functionality maybe provided by an AIN service node or by an Intelligent Peripheral, asthose terms are understood in the art. These components and others whichare operationally equivalent may be substituted for the CSN 112 in FIG.1.

Database 108 preferably comprises a data storage element for use withSCP 106 as known to those skilled in the art. Database 108 preferablystores account and call control information that can be implemented bySSP 102 to control calls. Such account and call control information isknown to those skilled in the art.

Database 110 preferably comprises a standard caller identification withname database as known to those skilled in the art. When the informationis available in the system, database 110 typically includes the name ofthe person associated with calling telephone station 118, along with thetelephone number that is associated with calling telephone station 118.Database 110 can alternatively comprise a caller assistance database asknown to those skilled in the art. While databases 108, 110 are depictedwithin a telecommunications system, databases 108, 110 can comprise anysuitable databases containing information adapted for use in the presentembodiment and are not limited to databases located within atelecommunications network. It is also important to note that whiledatabases 108, 110 are shown as separate components, they can beimplemented as a single database.

Central office 114 preferably comprises an AIN network switch as knownto those skilled in the art. Central office 114 enables calls to beplaced between calling telephone station 118 and called telephonestation 116. Alternatively, central office 114 can comprise a non-AINnetwork switch as known to those skilled in the art.

Telephone stations 116, 118 preferably comprise telephone sets as knownto those skilled in the art. The calling telephone station 118 can be ananalog telephone or, if associated with a subscriber line such as anISDN line, can be a digital telephone. The called telephone station 116may be a digital or analog telephone but in the illustrated embodimentis a digital telephone which communicates using digital signals with thePBX 120. Alternatively, telephone stations 116, 118 can comprisewireless, PCS, ISDN or any other form of communication station known tothose skilled in the art. In wireless embodiments, the PBX 120 may bereplaced with a mobile switching center (MSC) or other private equipmentaccessed over private trunk facilities such as private Trunk Group 122.Called telephone station 116 preferably includes CPE equipment for usewith caller identification services as known to those skilled in theart.

FIG. 2 is a call flow diagram illustrating a method for processing acall in the telecommunication system 100 of FIG. 1. FIG. 2 illustratescommunication between SSP 102, SCP 106 and CSN 112 for processing thecall.

At step 202, the calling party at the calling telephone station 118calls the directory number (DN) of the called communication station 116.The calling party may choose to enable Calling Number Delivery Blocking,for example, by dialing *67 before dialing the DN of the calledcommunication station 116. This will block delivery of the standardcaller ID information for the calling telephone station 118. In somesystems, portions of the telecommunications system 100 such as the trunkgroup terminating the call may not pass the standard Caller IDinformation.

At step 204, the terminating SSP 102 recognizes that a trigger isassigned to the called directory number. If the called communicationstation 116 is a conventional analog telephone accessed over aconventional subscriber loop, the trigger assigned to the calleddirectory number is a Terminating_Attempt Trigger. TheTerminating_Attempt Trigger is encountered by the SSP 102 when the calldirected to the directory number for the called telephone station isprocessed. If, as is shown in the illustrated embodiment, the calledcommunication station 116 accesses the network over private Trunk Groupfacilities such as the PBX 120 and Trunk Group 122, the triggerassociated with the called directory number is a Trunk_Group Trigger.All incoming calls on trunks associated with the directory number (DN)for the called communication station 116 that terminate over privatetrunk group facilities will encounter a Trunk_Group Trigger. TheTrunk_Group Trigger is encountered by the SSP 102 either on public orprivate facility trunk groups. If the SSP can not derive enoughinformation from the trunk group, it can obtain needed information fromtrigger line attributes associated with the trigger. The SSP 102encounters the Trunk_Group Trigger when a call is routed to thesubscribed trunk group.

In response to the either the Terminating_Attempt Trigger or theTrunk_Group Trigger, the SSP 102 creates a Termination_Attempt querymessage and transmits the query message to the SCP 106 for analysis. Inthe illustrated embodiment using AIN elements, the query message isformatted according to AIN Release 0.1 TCAP. The query message includesseveral parameters as is known to those ordinarily skilled in the art.For the Termination_Attempt query message, the following parameters arespecified, with specific parameters defined for instances ofencountering either a Termination_Attempt trigger or a Trunk_Grouptrigger:

UserID DN to which the trigger is assigned (Called DN) BearerCapability01 (3.1 KHz) CalledPartyID DN to which the trigger is assigned (CalledDN) Lata Local Access and Transport Area of Called DNTriggerCriteriaType 15 (terminating attempt, if a Terminating_Attempttrigger was encountered) 48 (terminating attempt, if a Trunk_Grouptrigger was encountered) CalledPartyStationType Originating LineInformation of the Called DN ChargeNumber ANI of the originatingfacility or ANI of last forwarding station, if available CallingPartyIDDN of the calling party (if available) Presentation Restriction 01(Presentation Restricted) 10 (Number Unavailable) 00 (Presentationallowed) ChargePartyStationType Originating Line Information of thecalling DN OriginalCalledPartyID First party that redirected the callRedirectingPartyID Last party that redirected the call

The Termination_Attempt trigger is assignable on a subscribed basis to adirectory number only. The trigger is assignable to either equipped orunequipped directory numbers. The Trunk_Group trigger is assignable on asubscribed basis to a private facility or public trunk group.

If the calling party has blocked the standard Caller ID information, orif the system does not pass the standard Caller ID information for thecalling communication station, the CallingPartyID parameter of theTermination_Attempt query message will not be available. ThePresentation Restriction Indicator parameter will be set to one of thebinary values 01 or 10 to indicate this condition. This is in contrastto the situation in which the standard Caller ID information isavailable and the Presentation Restriction Indicator parameter is set to00, to indicate presentation allowed.

In response to the Termination_Attempt query, the SCP 106 will validatethe Presentation Restriction Indicator parameter of the CallingPartyIDparameter. If the indicator is set to Presentation Restriction (01) orNumber Unavailable (10), the SCP 106 will pass routing information tothe SSP 102 in a Forward_Call response message, step 206. In anotherembodiment, the SCP 106 will examine account information stored at thedatabase 108. If the account information indicates that the called partyis a subscriber to privacy service, the SCP 106 will pass call controlinformation in the Forward_Call response message indicating this to theSSP 102. If the called party is not a subscriber, the SCP 106 willreturn an Authorize_Termination response message to SSP 102.

In the illustrated embodiment using AIN elements, the response messageis formatted according to AIN Release 0.1 TCAP. The response messageincludes several parameters as is known to those ordinarily skilled inthe art.

In a first embodiment, for the Forward_Call query message, the followingparameters are specified:

CallingPartyID DN to which the TAT is assigned and the DN associatedwith the Trunk_Group Trigger (Called DN from the Termination_Attemptquery with presentation allowed) CalledPartyID Lead DN from the ISDNtrunk group connecting the CSN; customer-selected language or formatoption PrimaryCarrier 0110 (LEC) AMAslpID 008780000 (uniquely identifiesa service and indicates flat rate)

Thus, in this first embodiment, the SCP 106 detects the CalledPartyIDparameter of the Termination_Attempt query received from the SSP 102. Asnoted above, this parameter is set to the DN of the called party, or thedirectory number of the called telephone station. The SCP 106 placesthis value in the Forward_Call response for the CallingPartyIDparameter. The CallingPartyID parameter of the Forward_Call response hasan associated Presentation Restriction Indicator parameter. The SCP 106marks this Presentation Restriction Indicator as presentation allowed.The SCP 106 sets a parameter in the call forward message indicating thata customer selected request message may be used for the input. Toindicate the customer-selected language or format option, an existingparameter of the Forward_Call query message is set to a predeterminedvalue. For example, this information may be incorporated in spare bitssuch as the last five digits of the CalledPartyID. Any other suitableparameter may be used for passing this information.

In a second embodiment, a different parameter is used in theForward_Call response message for communicating the called telephonestation's DN. This parameter is the RedirectingPartyID. In thisembodiment, the SCP 106 places the CalledPartyID DN from theTermination_Attempt query message into the RedirectingPartyID of theForward_Call response message. The RedirectingPartyID has an associatedPresentation Restriction Indicator parameter. The SCP 106 sets theassociated Presentation Restriction Indicator parameter to presentationallowed. In this embodiment, the Forward_Call query message hasparameters specified as follows:

CallingPartyID DN of the Calling Party (if available) CalledPartyID LeadDN from the ISDN trunk group connecting the CSN PrimaryCarrier 0110(LEC) RedirectingPartyID DN to which the TAT is assigned or the DNassociated with the Trunk_Group Trigger (Called DN from thetermination_attempt query) with presentation allowed (overwritesredirection information that the SSP would normally provide);customer-selected language or format option AMAslpID 008780000 (uniquelyidentifies a service and indicates flat rate)

At step 208, the SSP 102 receives the Forward_Call response message andoriginates a new call for the forwarded leg. The SSP 102 merges the neworiginating call and the existing terminating call. That is, the SSP 102bridges or reconfigures the call. At this point, the SSP 102 routes thecall as if it received an Analyze_Route message, using the CalledPartyIDin the Forward_Call message to identify the new party. In the firstembodiment described above, the CallingPartyID is the DN to which thetermination attempt trigger is assigned or the DN associated with theTrunk_Group. In the second embodiment, the redirecting number is the DNto which the termination attempt trigger is assigned or the DNassociated with the Trunk_Group. The SSP 102 forwards the call to theCSN 112.

At step 210, the forwarded call is answered by the CSN 112. The CSN 112is operative to generate an announcement that is transmitted to thecalling telephone station 118. In the illustrated embodiment, theannouncement is a request which is tailored according to called partyrequirements. One example of a suitable announcement is “The party youare calling does not accept calls from unidentified numbers. At thetone, say your name or the company you represent and your call will becompleted.” This may be the default message.

After transmission of the announcement to the calling party, the CSN 112then detects a response. If the calling party provides a response, theresponse is recorded as audible caller identification information forsubsequent playback to the called party. If no response is provided, thecall is terminated.

At step 212, the CSN 112 originates a new call to the called telephonestation 116. In the first embodiment described above, the CSN 112originates the new call to the DN found in the CallingPartyID parameterof the Forward_Call response message. The parameter was set to the DN towhich the Termination_Attempt trigger or the Trunk_Group trigger isassigned. In the second embodiment described above, the CSN 112originates the new call using the DN found in the RedirectingPartyIDparameter of the Forward_Call response message. The parameter was set tothe DN to which the Termination_Attempt trigger or the Trunk_Grouptrigger is assigned.

At step 214, the SSP 102 recognizes that a trigger is assigned to thecalled DN. If the called DN is a conventional subscriber loop, thetrigger will be a Termination_Attempt trigger. If the called DN is asubscriber associated with private trunk group facilities, as in theillustrated embodiment, the trigger will be a Trunk_Group trigger. Basedon the trigger, the SSP 102 creates a Termination_Attempt query messageand transmits the query message to the SCP 106 for analysis. Theparameters required for the AIN release 0.1 TCAP query message in theillustrated embodiment are as follows:

UserID DN to which the trigger is assigned (Called DN) BearerCapability01 (3.1 KHz) CalledPartyID DN to which the trigger is assigned (CalledDN) Lata Local Access and Transport Area of the Called DNTriggerCriteriaType 15 (terminating attempt, if a Terminating_Attempttrigger was encountered) 48 (terminating attempt, if a Trunk_Grouptrigger was encountered) CalledPartyStationType Originating Lineinformation of the called DN ChargeNumber ANI of the originatingfacility CallingPartyID DN of the calling party (CSN DN) PresentationRestriction 00 (Presentation Allowed) ChargePartyStationType OriginatingLine information of the calling DN

At step 216, the service logic of the SCP 106 will validate thePresentation Restriction Indicator of the CallingPartyID parameter ofthe query message. If the indicator is equal to Presentation Allowed,the SCP 106 will create an Authorize_Termination response message andsend it to the SSP 102. The parameters required for the AIN release 0.1TCAP response message in the illustrated embodiment are as follows:

CallingPartyID DN of the calling party (CSN DN) ChargeNumber ANI of thecalling party ChargePartyStationType Originating Line information of thecalling DN DisplayText CNAME information

At step 218, when the called party answers the called telephone station116, in the illustrated embodiment the CSN 112 first plays anidentifying message and requests a keypress input. This ensures that ahuman is present to answer the called telephone station 116 anddistinguishes the case where a modem, fax or other equipment answers thecalled telephone station 116. The identifying message may be in alanguage or format specified by the customer or called party at the timethe service is ordered. If the called party accepts the call, the CSN112 connects the original calling party at the calling telephone station118 to the called party at the called telephone station 116.

FIG. 3 is a flow diagram illustrating one embodiment of a method forprocessing a call in a telecommunications system including at least oneSCP, at least one SSP including a terminating SSP and private trunkfacilities such as a PBX or a public trunk group. The method allowssubscribers who access a network via private trunk facilities tosubscribe to and benefit from a privacy service of the network. In theillustrated method, a call is placed by a calling party at a callingcommunication station. The call is directed to the directory number of acalled party at a called communication station. The called communicationstation accesses the system via the private trunk facilities or publictrunk group. The method begins at block 300.

At block 302, the call is received at the terminating SSP. The incomingcall encounters a Trunk_Group trigger at the SSP for the calleddirectory number. The Trunk_Group trigger is provisioned against theprivate trunk group facilities of the subscriber when the subscriberadds the privacy service to his account. At block 304, in response tothe encountered Trunk_Group trigger, the SSP launches aTermination_Attempt query message to the SCP.

At block 306, the SCP determines if the called communication station isa subscriber to the privacy service (referred to in FIG. 3 as “APM”).The SCP in one embodiment consults a database of subscriptioninformation for the called directory number. If the called directorynumber is associated with a PBX, the owner of the PBX may be asubscriber and hence all DNs associated with the PBX will have theprivacy service provisioned against their account. In other situations,the individual DN may or may not have a subscription to the privacyservice.

If, at block 306, no subscription to the privacy service is found forthe called DN, at block 308 the SCP returns an Authorize_Terminationresponse message to the terminating SSP. The Authorize_Terminationresponse message directs the SSP to route the call to the PBX for thecalled DN, using the information currently available about the callingparty's identification information. At block 310, call processingcontinues normally.

Otherwise, at block 312, the SCP determines if standard calleridentification can be provided for the calling communication station.Two examples in which standard caller identification can not be providedare cases where there is a presentation restriction or where the calleridentification information is unavailable. If the Caller ID informationis not unavailable, meaning it can be provided, at block 314 the SCPtransmits an Authorize_Termination message to the SSP. In response tothis message, the SSP will complete the call to the called directorynumber. The call will be routed with the caller identificationinformation received for the call. At block 316, the call issubsequently processed normally.

If, at block 312, the standard caller identification information can notbe provided, at block 318 a Forward_Call response message is sent to theSSP. In this case, the privacy service is engaged and the call issuspended until the caller provides caller identification information.At block 320, the SSP responds to the Forward_Call response message byrouting the call to network equipment such as an AIN Service Node orIntelligent Peripheral, which are collectively referred to in FIG. 3 asa SN/IP. At block 322, call processing continues normally.

As can be seen from the foregoing, the present embodiments provide asystem and method for delivering audible caller identificationinformation when standard Caller ID information can not be provided,even for subscribers who access the network through private facilitiesor public trunk groups. For such subscribers, the Trunk_Group Triggerwill be provisioned against the trunk group associated with their DNwhen they subscribe to the privacy service. When a call is received, theTrunk_Group trigger is encountered and an termination attempt querymessage is initiated to an SCP. The SCP routes the call to a servicewhich requires that the calling party state a name for playback to thecalled party or enter an access code. In one particular embodiment, theSCP detects the directory number to which a terminating attempt triggeris assigned or a directory number associated with a trunk group to whicha Trunk_Group Trigger is assigned and places this directory number in aparameter for transmission to the SSP using a Forward_Call message. TheSCP prompts the calling party to provide audible caller identificationinformation. The called party is then advised of the incoming call.

It is to be understood that a wide range of changes and modifications tothe embodiments described above will be apparent to those skilled in theart and are contemplated. It is therefore intended that the foregoingdetailed description be regarded as illustrative rather than limiting,and that it be understood that it is the following claims, including allequivalents, that are intended to define the spirit and scope of theinvention.

1. A telecommunications method comprising: detecting, by a serviceswitching point (SSP), a call from a calling party at a callingcommunication station to a called party at a called communicationstation which is associated with a private trunk group; detecting, bythe SSP, a private trunk group trigger associated with the calledcommunication station; and generating, by the SSP, a termination attemptmessage in response to the private trunk group trigger, wherein thetermination attempt message requests call routing information andincludes called party identification information; receiving, by the SSP,call routing information in response to the termination attempt message;generating, by a compact service note (CSN), in response to the callrouting information, a request for audible caller identificationinformation at a privacy service; and transmitting, by the CSN, therequest for audible caller identification information to the callingparty.
 2. The method of claim 1 wherein receiving call routinginformation comprises: receiving a termination message if the calledparty is not a subscriber to the privacy service.
 3. The method of claim2 wherein receiving call routing information comprises: receiving atermination message that includes calling party identification for thecalling communication device if standard calling party identificationinformation can be provided for the calling communication device.
 4. Themethod of claim 3 wherein receiving call routing information comprises:receiving a forward call message that directs the call to networkequipment to initiate a privacy service call at the privacy service ifstandard calling party identification information can not be providedfor the calling communication device.
 5. A telecommunications methodcomprising: detecting, by a service switching point (SSP), a call from acalling party at a calling communication station to a called party at acalled communication station associated with a private trunk group;determining, by a compact service node (CSN), whether standard callingparty identification information can be provided for the call;initiating, by the CSN, a new call from a privacy service to transmit arequest for audible caller identification information to the callingcommunication station if standard calling party identificationinformation can not be provided for the call; and transmitting, by theCSN, the audible caller identification information from the privacyservice to the called communication station associated with the privatetrunk group.
 6. The telecommunications method of claim 5 furthercomprising: detecting, by the CSN, call routing information associatingthe called communication station with the private trunk group.
 7. Thetelecommunications method of claim 5 further comprising: detecting, bythe SSP, a private trunk group trigger associated with the calledcommunication station.
 8. The telecommunications method of claim 7further comprising: generating, by the SSP, a termination attemptmessage for the call in response to detection of the private trunk grouptrigger; determining, by the CSN in response to receipt of thetermination attempt message, whether the standard caller identificationinformation can be provided.
 9. The telecommunications method of claim 7wherein transmitting a request for audible caller identificationinformation comprises: prompting the calling party to state identifyinginformation; and recording the stated identifying information as theaudible caller identification information.